Cetuximab may not be cost effective for colorectal cancer

The drug has high incremental cost-effectiveness ratios compared with best supportive care.

The use of cetuximab to treat metastatic colorectal cancer was more cost effective in patients with wild-type KRAS, according to the conclusions of a study published in the Journal of the National Cancer Institute. However, even in those patients with wild-type KRAS assigned the drug the incremental cost-effectiveness ratio was high compared to best supportive care, researchers concluded.

Results of the study showed that in patients with wild-type KRAS the mean gain in survival seen with the use of cetuximab (Erbitux, ImClone Systems) resulted in a mean incremental cost effectiveness ratio of $120,061 per life-year gained.

In an accompanying editorial , K. Robin Yabroff, PhD, of the National Cancer Institute, and Deborah Schrag, MD, MPH, of Dana Farber Cancer Institute, wrote that although Nicole Mittmann, PhD, and colleagues were able to show that cetuximab was more cost effective in patients with wild-type KRAS, they also showed that the cost-effectiveness “is still higher than thresholds commonly used to identify ‘good value.’”

“These findings raise important questions about the use of cost-effectiveness analysis in policy making,” they wrote. “In a setting with unlimited resources, all effective therapies — even those with modest survival benefits — could be offered to every patient. But, because in most settings, resources are limited, publicly funded health-care programs, health plans, and other policy makers must weigh the costs and benefits of different treatments and make decisions about which treatments will be covered and under what circumstances.”

Cost-effectiveness analysis

Mittmann, of the HOPE Research Institute Centre Sunnybrook Health Sciences Centre, Toronto, and colleagues prospectively collected resource utilization and health utility data including medications, office visits and hospitalizations from 572 patients in the National Cancer Institute of Canada Clinical Trials Group CO.17. Two hundred eighty-three patients had been randomly assigned cetuximab; 274 were assigned to best supportive care.

Researchers determined KRAS status retrospectively for 394 of patients in the total cohort and found that 58% had wild-type KRAS; 117 in the cetuximab group and 113 in the supportive care group.

Overall, the incremental cost with cetuximab was calculated to be $23,969 more per patient compared with the supportive care group. Cetuximab conferred a mean survival gain of 0.12 years (7.7 months vs. 6.2 months). The survival advantage resulted in a mean incremental cost-effectiveness ratio of $199,742 per life year gained.

“Cetuximab resulted in a mean gain of 0.08 quality-adjusted life years, with a mean incremental cost-utility ratio of $299,613 per quality-adjusted life year gained,” the researchers wrote.

Costs were higher for patients with wild-type KRAS compared with those in the supportive care group but the drug conferred a greater survival advantage, with a mean gain of 0.28 years. Patients with wild-type KRAS had a mean survival of 9.5 months when assigned cetuximab compared with 6.1 months in the supportive care group. The researchers said the improved survival resulted in a mean incremental cost-effectiveness ratio of $120,061 per life-year gained.

Patients with wild-type KRAS assigned cetuximab gained 0.18 quality-adjusted life years, resulting in a mean incremental cost-utility ratio of $186,761 per quality-adjusted life-years gained.

The researchers noted that they did not take the cost of testing for the KRAS mutation into account because that cost applied to both groups in this study. Yabroff and Schrag said that expense would need to be taken account if these results were to be applied to a broader population.

“Extrapolation of these trial-based estimates to the general population would need to consider the cost of KRAS mutation testing and would likely lead to even higher incremental cost-effectiveness ratios for cetuximab therapy outside a trial setting,” they wrote.

Mittman N. J Natl Cancer Inst. 2009;101:1-11.

Yarbroff KR. J Natl Cancer Inst. 2009;101;1044-1048.